"The Metal Monster" by Abraham Merritt is a fantasy novel first serialized in 1920. Dr. Goodwin ventures into the Trans-Himalayan mountains on a botanical expedition, where he and his companions encounter a mysterious woman named Norhala who commands living metal creatures—sentient geometric forms capable of combining into colossal shapes wielding devastating weapons. Trapped between this alien metal civilization and an army of ancient Persians in a hidden valley, the group must find escape while one of their own slowly transforms into something inhuman. (This is an automatically generated summary.)